https://invisible-island.net/xterm/xtoolkit/
XtRegisterGrabAction - register button and key grabs
#include <X11/Intrinsic.h>
void XtRegisterGrabAction(XtActionProc action_proc, Boolean
owner_events, unsigned int event_mask, int pointer_mode, int
keyboard_mode);
action_proc
Specifies the action procedure to search for in translation
tables.
action
event
params
num_params
Specify arguments to XtGrabButton or XtGrabKey
XtRegisterGrabAction adds the specified action_proc to a list known to
the translation manager.
X Toolkit Intrinsics - C Language Interface
Xlib - C Language X Interface
X Version 11 libXt 1.3.1 XtRegisterGrabAction(3)